T.S.A of hemisphere = 3πr2\pi r^2πr2
vol of hemisphere = 23πr3\; \frac{2}{3} \pi r^332πr3
3πr2\pi r^2πr2 = 23πr3\; \frac{2}{3} \pi r^332πr3
3 = 23r\; \frac{2}{3} r32r
9 = 2r
r = 92\; \frac{9}{2}29
r = 4.5cm
